Combustion method for fuels



April 15, 1930. E. VOLCKER COMBUSTION METHOD FOR FUELS Filed March 1,1923 5 Sheets-Sheet l JME April 15, 1930. 5 vbLcKER 1,754,586

COMBUSTION METHOD FOR FUELS Filed March 1, 1923 5 Sheets-Sheet 2 April15, 1930. E. VCLCKER comsusnon METHOD FOR FUELS 5 Sheets-Sheet 3 FiledMarch 1, 1923 April 15, 1930. E. VCLCKER COMBUSTION METHOD FOR FUELSFiled March 1, 1925 5 Sheets-Sheet 4 April15, 1930. IOL KER 1,754,586 7COMBUSTION METHOD FOR FUELS Filed March 1, 1925 5 Sheets-Sheet 5Patented Apr. 15, 1930 PATENT OFFICE muse v'encsm oF' selenium,GERntAiIit comntrsuuoirmn rnon Fem-mm Application filed lllarhl, 1923;Serial No. 622,180; and in Geri'nanyMarch 23, 1922.

This invention relates to furnaces with in clined grate'or withtravelling grate which produce unfavorable combustion conditions if thefurnaceis' used for the combustion of inferior fuel having a highpercentage of moistness, for instance lignite. It has already beenproposedto' improve the combustionby sucking off by means of fans aportion ofthe fluegas and to conductit to the front 1 portion of thegrate surface, no practically valuable result having, however, beenobtained. d

This invention relates to a new method for improving the combustion onthe grate, according to which method a portion of the flue gases isautomatically deflected by the action of the kinetic energy inhering inthe flue gases and'to conduct this deflected portion of the flue gasesbackward to one or sev- 5 eral points of the front portion of the gratesurface. This method mightbe modified by automatically branching offportions of the flue gases at different pointson the rear part of thegrate and to conduct these deflected portions to different points on thefront part ofthe grate. v

With this object in view the inner construction of the furnace isimproved by arranging over the front half of the grate a resistance archandpreferab'ly also a radiating vault havinga concave lower surface andan inclined rear guiding surface in front of a re turn channel of thevault, said return channel being branched at-the front end so that thegas flows can be conducted to separate sections of the grate.

Ithas therefore already been proposed to withdraw fromthe rear part ofthe grate a part of the flue gas by mechanical means, for instance bysucking'ofl, and to conduct the same to-the front part of the grate inorder to improve the combustion upon this part of the grate. Theseexperiments have however r not given up to the present any favorableresult.

The invention is based upon the idea to utilize the kinetic energy ofthe highly valuable fluegas for bringing back to the front part r,of-the grate part of said flue gas with the aid of conveniently arrangedguiding surfaces without the use of any mechanical means, in order touse this part of the flue at a convenient point of the furnace forimproving and perfecting the combustion process, it beingindifierentwhether the furnaceis supplied with solid, liquid or gaseousfuels.

. Several'embodiments of the invention are illustrated in theaccompanying drawings, wherein:

igure; shows in side elevation partly in section a half-gas firedfurnace with inclined grate.

Figure 2 shows in side elevation partly' in section a half-gas firedfurnace with inclined grate and feeding chute.

Figure 3 shows in side elevation partly in section a furnace plant withtravelling grate.

Figures i and 5 show a furnace with vertical feeding chute inlongitudinal section and front elevation, respectively. v

Figure 6 shows in crosssection a vertical feeding chute of specialshape.

Figure 7 isa vertical sectional view on the lineil I of Figure 1. H i

The furnace shown in Fig. l consists'of the upper inclined grate 1, thelower inclined grate 2, the flat grate 3, the space 4! for thepreliminary drying, distillation or degassing with the movable bridge 5,the radiating vault 6 and theresistance arch 7. A

The radiating vault 6 has a concave lower surface and at the rear end aninclined downwardly'. and rearwardly projecting beakshapedguidingsurface 8. The radiating vault is traversed in longitudinal directionfrom one side to the, other by a channel 9 which is branched off at thefront end into two arms 10, 11 of which the one, 10, terminates in thedegassing or distillation s ace 4:, the other, 11,, terminating in theurnace proper 12. The side Walls of the furnace proper haveprojections13 interrupted at 14 and the resistance arch 7 has a beak-shaped guidingsurface 15'which extends in inclined direction upwardly and forwardly.

The guiding surface, 8 of' the radiating Vault conducts part of thehighly valuable flue gas under. the radiatingvault 6. Another part thisgas is conducted under the radiating vault by means of the narrowsinglyor in pairs.

ing of the furnace produced by the projections 13 in flowing through theopen parts 14. All these deviated highly valuable flue gases whirl inthe direction indicated by arrows through the space situated between theradiating vault and the front surface of the grate and improve thecombustion at this part of the furnace so that it becomes moreintensive.

The resistance arch 7 situated on the path of the flue gases issurrounded above and below by the outflowing highly valuable flue gasesin such a manner that approximately th of the gases flow off below andth above said arch. The beak-shaped guiding surface of the resistancearch deflects part of the highly "aluable flue gas (about th) into thechannel 9 of the radiating vault 6. In this channel the flue gas isseparated into two currents, approximately th flowing through tube 10into the degassing space 4 and approximately /;.,th through the nozzleshaped tube 11 into the furnace proper 12 where the gas flows along therear wall of the bridge 5 sucking off gases of distillation from thedegassing space 4 mixing intimatel with these gases and finally admixwith the above mentioned highly valuable flue gases.

The fuel is preliminarily dried, owing to the above describedcirculation of the highly valuable flue gases so far that it sticks nolonger but slips down regularly and is inflamed easily. The radiatingvault is fur ther heated to red heat and its concave lower surfaceradiates the heat backward upon the inclined grate 2 and the bridge 5for the indirect drying of the fuel. The mixed gases having completedtheir circulation in the furnace proper flow off over the grate 3 wherethey are burnt to form highly valuable flue gas.

The furnace shown in Fig. 2 consists of the inclined grate 16, thepoking carriage 17, the flat grate 18, the resistance arch 19 with thebackward guiding surface 20 and the passages 21, the radiating "ault 22with concave lower part, the channel 23 and the feeding chute 24.

The front and rear Walls of the feedin chute 24 are interrupted byinclined slits an one or several registers 25 for regulating theadmission of the air. Four registers are preferably arranged upon thewhole front wall said registers being adapted to be adjusted The lowerextension of the rear wall of the feeding chute forms a movable bridge26, adapted to be operated from the stokers stand and through which thegases of distillation flow from the dis tillation space into the frontpart of the furnace proper 27. The gap between the front wa-l of thefeeding chute 24 and the inclined grate 16 adjustably mounted in a link28 is filled by a flap 29 suspended so that it can freely swing andmaintained in the closing position by the fuel on the feeding chute. Thechannel 23 of the radiating vault 22 is adapted to be shut off more orless by a register 30.

The current of flue gas flows in this form of construction along thesame path as described with reference to Fig. 1. Part of the highlyvaluable flue gas is conducted by the beak-shaped extension 20 of theresistance arch 19 into the chamber 23 where it heats the radiated vault22 and the rear wall of the feeding chute and of the bridge 26,

sucks off the gases from distillation from the degassing space andforms, together with gases from distillation in the space 27, a mixturewhich is burnt upon the grate. As the fuel, owing to the arrangement ofthe bridge 26 and of the flap 29 has to travel a long way beforearriving at the grate, the action of the deflected flue gas upon thefuel is increased. This action can be regulated by adjustment of theregisters 25 and 30. At the same time irregularities in the feeding ofthe fuel are avoided and a uniform feeding of the grate is ensured sothat no gaps in the fire on the grate nor idle burning of the fire canoccur.

The furnace shown in Fig. 3 comprises a travelling grate 31, theradiating vault 33 with the concave lower surface and downwardlyinclined beak 32 and channel 34, the resistance arch 35 with beak 36upwardly directed in inclined position and the feeding chute 37 withperforated front and rear walls.

A part of the highly valuable flue gas is deviated in the directionindicated on the drawing by arrows and conducted backwards through thechannel 34 of the radiating vault When coming out of this channel 34 thedeviated flue gas flows downward along the rear wall of the feedingchute so that the coal is dried, whereupon the flue gas, together withthe gases from distillation, flows over the grate. v

This installation is specially designed for inferior fuels for instancefor lignite. With fuel of this kind travelling grates could hitherto notbe used as the coal baked in the feeding chute and as the fire wasinterrupted upon the grate directly behind the feeding chute so thatgaps in the fire were produced upon the grate. These inconveniences areavoided by part of the highly valuable flue gas being conducted back inaccordance with the invention so that travelling grates may now be usedalso for lignite and similar fuels.

Part of the gas from distillation produced at the preliminary drying ofthe fuel does unfavorably influence, owing to its high percentage ofsteam, the general temperature in the furnace and consequently thecombustion process as the preliminary drying and the dis tillation ofthe fuel are different in the several superposed zones of the feedingchute so that they increase in intensity the closer the zone is situatedto the grate. The prejuiii.

creates dicial action of the gases from distillation upon the efficiencyof the furnace is particularly pronouncedif part of the flue gas isconducted backward in accordance with the invention as in this case thepreliminary drying of the fuel is more intense than hitherto.

According to the invention the gases from distillation are thereforesubdivided and the noxious parts of the same are sucked off, the usefulpart being however conducted to the furnace as illustrated in Figs. 4and 5.

This furnace comprises also the radiating vault 38 with concave lowersurface, with beak-shaped guiding surface 39 and with channel 40, theresistance arch 4:1 with guiding surface 42 and the feeding chute 43.This feeding chute has, similar to the above described form ofconstruction, a perforated front and rear Wall. Upon the front Wall asuction device 44 communicating with the main flue of the furnace isadjustably arranged in lateral guides 45 so that it extends over theentire height of the feeding chute.

The fuel in the vertical feedincr chute is preliminarily heated by theback flowing flue gas which traverses the channel 40 of the radiatingvault 38 and descends alon the rear wall of the feeding chute. Theadjustable suction device permits to determine by sucking off andanalyzing the gas thelimit, according to the kinds of fuel used up towhich the gases from distillation ave a prejudicial effect and at whichpoint of the feeding chute they have to be removed. Supposed the entireheight of the feedin chute comprised five zones the gases fromdistillation will consist at the middle zone for the largest part ofsteam and of inferior coal gases from distillation which are ballast forthe furnace and which forthe largestpartwill therefore be directlyconducted into the main flue by the suction device without otherauxiliary means.

The most extensive utilization of the backward conducted highly valuableflue gas for the preliminary drying of the fuel will be possible if thedistilling process per se is effected under the most favorableconditions. The distilling process depends on the kind of fuel, on thepercentage of moistness of the fuel and on the thickness of the fuellayers in the feeding chute.

The unfavorable influence upon the distilling process of the kind offuel and of the percentage of moistness which varies continuously underthe influences of temperature must be compensated by variation of thethickness of the fuel layers.

According to the invention the feeding chute is therefore made withvariable cross section as shown in Fig. 6.

The feeding chute 45 has a perforated front wall 46 and a perforatedrear wall 4:7. The rear wall is bricked in solidly but the front wall 46is adjustable upon fixed sliding rails 48 with the aid of screw bolts'459'. The cross section of the feeding chute istherefore variable andconsequently X the thicknesses" of the layers of fuel are variable also.

I claim p 1. In afurna'ce, the combination 1 with gratc'forsi-ippo'f'tiif ffu el to be burnt injt'he furnace and an outlet flue inthe rearof the furnace for the exit of hdtgasesfroni the furnace, of adeflecting member interposed in the path of the hot gases flowingthrough said outlet and guiding means arranged in the furnace adapted toco-"operatewith defleeting member for guiding a portion of said gases tothe front of the furnace so as to ene able said portion ofthe gasest'obe returned tlfereto bythei'r kinetic energy. V

2. Ina furnace, the combination witha grate for supporting fuelto be'burntin the furnace and an outlet flue in the rear of the furnace forthe exit of hot gases from the furnace, and a radiating vault above saidgrate, said vault having a concave lower surface, of projections on saidvault for whirling the hot gases in the space below said vault andguiding means, including a deflecting member interposed in the path ofthe hot gases flowing through said outlet, for guiding a portion of saidgases to the front of the furnace so as to en able said portion of thegases to be returned thereto by their kinetic energy.

3. In a furnace, the combination with a grate for supporting fuel to beburnt in the furnace and an outlet flue in the rear of the furnace forthe exit of hot gases from the furnace, of a flue for establishing opencommunication between the front and the rear of the furnace, said fluehaving its rear end terminating in close proximity to the said outlet,and a resistance arch extending across said outlet flue for interceptinga portion of the hot gases flowing to said outlet, said resistance archhaving a guiding surface for defleeting said portion of the hot gasestowards the rear end of said flue, for the purposes set forth. I

4. In a furnace, the combination with a grate for supporting fuel to beburnt in the furnace, an outlet flue in the rear of the furnace for theexit of hot gases from the furnace, and a radiating vault above saidgrate, said vault having a lower concave surface, of a bridge arrangedin front of said radiating vault, a flue for establishing opencommunication between the front and the rear of the furnace, said fluehaving its rear end terminating in close proximity to said outlet andits front end terminating behind said bridge,

means for establishing open communication between said front end and thespaces in front of and behind said bridge, respectively, and aresistance arch extending across said outlet flue for intercepting aportion of the hot gases flowing to said outlet, said resistance archhaving a guiding surface for deflecting said "sit portion of the hotgases towards the rear end of said flue, for the purposes set forth.

5. In a furnace, the combination with a grate for supporting fuel to beburnt in the furnace and an outlet flue in the rear of the furnace forthe exit of hot gases from the furnace, of a flue for establishin opencommunication between the front an the rear of the furnace, said fluehaving its rear end terminating in close proximity to the said outlet, aregister in said flue for throttling the passage of the hot gasestherein, and a resistance arch extending across said outlet flue forintercepting a portion of the hot gases flowing to said outlet, saidresistance arch having a guiding surface for deflecting said portion ofthe hot gases towards the rear end of said flue, for the purposes setforth.

In testimony whereof I atlix my signature.

ERNST VGLCKER.

